The present invention relates to a semiconductor device having a memory element such as MTJ (Magnetic Tunnel Junction) element and a manufacturing method of the device.
MRAM is a memory which uses a magnetic material as its memory element and stores data, depending on the direction of magnetization of the magnetic material, in other words, a memory which retains data therein by storing information in the spin of electrons. The circuit of it is configured to allow random access. A memory element utilized as MRAM is, for example, an MTJ element. In this specification, the term “MTJ element” is used as a concept embracing a TMR (Tunneling Magneto Resistance) element.
Conventional MTJ elements (MTJ elements of a first kind) undergo a change in the resistance due to a magnetic field from the outside. Such typical MTJ elements (TMR elements) are disclosed, for example, in Japanese Unexamined Patent Publication No. 2006-156608.
Conventional MTJ elements (MTJ elements of a second kind) called “STT (Spin Torque Transfer)-RAM” undergo a change in the resistance by a current flowing through itself. Such MTJ elements called “STT-RAM” are disclosed, for example, in Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2005-535125.